Dental instrument



April 6, 1937. F. H. DONER DENTAL INSTRUMENT Filed May 8, 1935 Patented Apr. 6, 1937 UNITED s'ras PATENT OFFICE DENTAL INSTRUMENT Frederick H. Doner, Watertown, N. Y.

Application May 8, 1935, Serial No. 20,467

4 Claims.

The present invention, consisting of a dental instrument, is especially adapted for use in preparing a tooth for the reception of a jacket crown. It is well known in the art to provide tools or instruments for surface polishing or grinding of teeth, but they are incapable of producing a smooth symmetrical periphery with which the crown may be readily and effectively engaged.

Objects of the invention are to provide an in m strument capable of conditioning any type of tooth preparatory to engaging a crown with the latter; to provide an instrument which will re-.

move the enamel from a tooth and definitely shape the latter for the crown; to provide an instrument which will form a well defined shoulder to act as an abutment for the inner terminal of the jacket; to provide an instrument capable of use in the presence of a lubricant whereby frictional heat is reduced to a minimum and time, required for preparing the tooth, correspondingly conserved; and to provide. an instrument capable of forming an abutment on the tooth above the gum line without injury to the soft gum tissues.

Other objects of the invention. will be apparent from the following description of the present preferred form of the invention, taken in connection with the accompanying drawing, whereinz- Fig. 1 is a perspective view of a dental instrument constructed in. accordance with the present invention showing to advantage the manner of mounting the abrasive body in the cylindrical cup.

Fig. 2 is a fragmentary vertical sectional view of the same showing the manner of connecting the cup to the mandrel and also showing a cylindrical abrasive body mounted in the cup.

Fig. 3 is a vertical sectional view of one form of abrasive cylinder.

Fig. 4 is a similar view of a modified form of abrasive body in which the inner surface of the bottom wall is flat.

Fig. 5 is a similar view in which the inner surface of the bottom wall is provided with a projection.

Fig. 6 is a similar view in which the bottom wall X is provided with a recess.

Fig. 7 is a vertical sectional view of a cylinder the free edge of which is serrated.

Fig. 8 is a top plan view of the same.

Fig. 9 is a detail fragmentary sectional view of a sand paper finishing cylinder, and

Fig. 10 is a side elevational view of a tooth after it has been prepared for the reception of a porcelain jacket crown in accordance with the teaching of the present invention.

The device of the present invention consists of a mandrel II which is adapted for engagement with a dental hand machine in a manner well known in the art. One end of the mandrel is adapted for detachable engagement with the bottom of a. cylindrical cup I2 through the medium 5 of a 'screw I3. The cup may be made of any suitable material, preferably metal and of any desired size convenient for the performance of the work.

The cup I2 is adapted for the reception of any one of a series of abrasive bodies, generally des- 10 ignated I4. The abrasive body shown. in Fig. 2, indicated M is a straight cylinder, one end of which abuts the bottom of the cup I2 while the opposite end lies flush with the free and outer end of the cup. The body shown in Fig. 3, indicated 1 I4 tapers inwardly toward its inner end. The body shown in Fig. 4, indicated H! is cylindrical and equipped with a bottom I5, the inner face of which is fiat. The body shown in Fig. 5, indicated I 4 is also provided with a closed bottom I5, from the inner wall of which a pointed projection 56 issues. The body shown in Fig. 6, indicated I4 is provided with a closed bottom I5 which is provided with a central conical recess I'l.

All of these bodies are adapted for difierent 2 types of teeth. For instance, the abrasive body shown in Figs. 2, 3, and 4 is adapted to prepare incisor teeth. The body shown in Figs. 2, 3 and 5 is adapted for use with bicuspid teeth, while the body shown in Figs. 2, 3 and 6 is adapted for use in preparing cuspid teeth. As is apparent, the projection shown in Fig. 5 of the abrasive body operates in the furcation or interstice of a bicuspid.- On the other hand, the form of abrasive bodyzshown in Fig. 6 is adapted for the reception oi the pointed terminal of a cuspid.

In using the abrasive body shown in Figs. 1 to 6, inclusive, not only is the enamel removed from the tooth, but in addition the latter is made smooth to permit the jacket to be slipped thereover with facility. Furthermore, since the outer margin of the abrasive body is flush with the free terminal of the cup, a shoulder is formed on the tooth to provide an abutment against which the inner end of the jacket will engage.

It sometimes becomes desirable to form a shoulder beyond the gum line and, of course, it is necessary to do this without injury to the investing soft tissues. For this purpose, I have in Figs. '7 and 8 shown a thin metal cylinder I8 adapted to be mounted in the cup I2. The outer end of the cylinder is serrated, as indicated at I9, the line of the serrations being flush with the outer end of the cup. By use of this cylinder the shoulder may be quickly and effectively formed without tearing into the gum tissues.

After the enamel has been removed from a tooth, it is desirable to polish the same, and for this purpose, I have in Fig. 9 shown a sand paper cup or cylinder 20. The inner surface of the cup or cylinder is roughened while the outer periphery is equipped with an adhesive through the medium of which the cup or cylinder is secured in the instrument cup l2.

In use of this instrument, it is desirable to employ cocoa-butter or some other lubricant which is mounted in the cup in order to reduce frictional heat to a minimum. The instrument is of course rotated in a manner well known in the art until the tooth is prepared to a point where it may be readily engaged by the porcelain jacket crown. In Fig. 10, I have shown an incisor tooth after it has been abraded and polished in accordance with the teaching of the present invention preparatory to receiving the jacket crown.

I am, of course, aware that various changes may be made in my invention, especially in the details of construction, proportion and arrangement of parts, within the scope of the appended :claims.

aye/6,445

What is claimed isi 1. A dental instrument for use in preparing a tooth for a jacket crown, including a mandrel for a dental hand piece, a cylindrical cup on the mandrel, and a. preformed abrasive cylinder detachably mounted in the cup, said cylinder being flush with the free end of the cup to form a shoulder on the tooth being prepared.

2. A dental instrument for use in preparing a tooth for a jacket crown, including a nonbreakable cup and a hollow preformed abrasive body mounted in said cup, said body being flush with the free end of the cup to form a shoulder on the tooth being prepared.

3. A dental instrument including a cup, and an abrasive body detachably mounted in said cup, the bottom of said body being provided with an enlargement for cooperation with a tooth.

4. A dental instrument, including a cup, and an abrasive body complementing said cup and detachably mounted therein, the bottom of said body being provided with a recess to receive the outer terminal of a cuspid tooth.

FREDERICK H. DONER. 

